assemble_package: Takes a local package and assembles it
In DanteBortone/housekeeping: Basic Debugging and Package Building Tasks

Takes a local package and assembles it

1	assemble_package(package_name, my_version, my_dir, should_build = FALSE)

`package_name`	string name of the package
`my_version`	string version the package should be named
`my_dir`	directory path to the package
`should_build`	flag to indicate whether a tar.gz should be built or not

No return value

Modifies the version listed in the DESCRIPTION file
Deletes the tar file from any older packages
Runs roxygen on the package
Builds the package
Tries to load the package. If it doesn't work, the DESCRIPTION file version name is set back to what is was.